Test::Builder object

As we saw earlier, Test::Builder is the backbone of the testing framework of Perl.
The Test::Simple, Test::More are built on top of this module and there hundreds of other modules in the Test::* namespace on CPAN
that use this same back-end. All those modules provide extra testing functionality.

Though actually there are a few modules in the Test:: namespace that are not "testing modules" in the same way as the the ones we are
talking about here, but the majority can be loaded in any test script and the majority provide extra testing functions.

As we create is_any, other created lot os other such functions and modules.

There are effecively hundresds of these modules and we'll take a look at quite a few of them. For now though, I'd like to say a few words
about Test::Builder and hopefully eliminate a confusion that I lived in for quite some time.

During the execution of a test script there is only one Test::Builder object. It is a singleton.
It can be retreived in at least 3 ways, and different pieces of examples (even by the same person) might use more than one of them:

This script shows you the 3 common ways people use it and show it in their examples: